Net Income per Common Share - Reconciliation between basic and diluted net income per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2022	Oct. 31, 2021	Oct. 31, 2022	Oct. 31, 2021
Net Income (Loss) per Common Share
Net income attributable to G-III Apparel Group, Ltd.	$ 61,103	$ 106,674	$ 128,056	$ 152,163
Basic net income (loss) per share:
Basic common shares	47,488	48,567	47,832	48,474
Basic net income (loss) per share (in dollars per share)	$ 1.29	$ 2.20	$ 2.68	$ 3.14
Diluted net income (loss) per share:
Basic common shares	47,488	48,567	47,832	48,474
Diluted restricted stock awards and stock options	987	891	1,034	1,025
Diluted common shares	48,475	49,458	48,866	49,499
Diluted net income (loss) per share (in dollars per share)	$ 1.26	$ 2.16	$ 2.62	$ 3.07